When that picture was taken, I had four ISA Brown hens. They all made it through that first winter. I lost one in the spring of 2019, and the remaining three sailed through this past winter as well. Then again, I lost another one back in May. The remaining two ISA Browns will be going through this winter with some new pullets. Joining the original two ISAs, are two Buff Orpington, two RIR, and 4 Barred Rock, one of which is a cockerel. Same coop, bigger run this year. From what I've read, all the breeds I have are cold hardy. They are also all quite a bit larger than my ISA Brown hens...especially one of my Orpingtons who is a colossal pullet!
Now, the ISAs didn't come out of that first winter unscathed. They all lost the points of their combs. I don't believe there was anything I could do to avoid that, not when the temperatures get as cold as they do here. I'm a bit worried for my cockerel, and his massive comb and wattles. Poor guy, he's going to have a new look by spring.